An oral device for improving the breathing of a user by means of protrusion of the lower jaw includes a first dental rail that covers at least some teeth of a lower row of teeth of the user a second dental rail that covers at least some teeth of an upper row of teeth of the user and at least one coupling element connecting the first and the second dental rail. The first dental rail comprises a front, labial connection point and the second dental rail has two rear, buccal connection points positioned substantially at its two posterior ends. The coupling element has a substantially U-shaped configuration, and an apex of the coupling element forms a joint with the front labial connection point on the first dental rail. The posterior ends of the coupling element form a joint with the rear connection points of the second dental rail.
